Control means



Dec. N9 R950 R. J. lFlELD 2,534,821

CONTROL MEANS Filed Dec. 6, 1946 1 17 I" o 1 e sf 22 l? 9` 7 13 s I 10 I ,s no 1 [D 1:) y I .1i/I f Vf i Patented Dec. 19, 1950 CONTROL MEANS Richard Joseph Ifield, Birmingham, England, as-

signor to Joseph Lucas Limited, Birmingham,

England Application December 6, 1946, Serial No. 714,582 In Great Britain October 23, 1945 Section 1, Public Law 690, August 8, 1946 Patent expires October 23, 1965 6 Claims.

In certain systems used for supplying liquid fuel to internal combustion prime movers there is 'lated in a satisfactory manner over a wide range of load conditions, and also over a wide range of variations of atmospheric pressure.

The invention comprises a means for establishing in the pipe system between the pump and the combustion chamber, a pressure difference which can be utilised for regulating the fiow of liquid to the nozzle or nozzles, the said means having a pair of orifices arranged in parallel, a movable member responsive to variations of atmospheric pressure for varying the effective areas of the orifices, and a manually operable valve for controlling the ow through one of the orifices.

The accompanying drawing is a diagrammatic sectional side elevation of a means constructed in accordance with the invention and arranged in association with a variable delivery liquid fuel pump of the swash plate type.

The liquid fuel pump shown in the drawing comprises a rotary cylinder block a arranged in a casing b and having formed around its axis a plurality of bores as c in each of which is arranged a reciprocatory plunger as d. The cylinder block a is adapted to be driven in any convenient manner. During rotation of the cylinder block a the plungers d are moved in one direction by an angularly movable swash plate e and in the opposite direction by springs as f, the latter being situated within the bores c, and serving to hold an end face of the cylinder block in contact with a flat seating g in the casing b. The seating g is formed with a fuel delivery outlet and with a liquid fuel inlet (not shown).

In one end of the casing bis formed a cylinder j having closed ends. Within the cylinder i is arranged a piston k loaded by a spring m, and extending from one side of this piston through a bore in the inner end of the cylinder is a rod n connected to the swash plate e. The inner end of the cylinder y is in free communication with the outlet i through a passage o, and it also communicates with the other or outer end of the cylinder (which contains the spring m) through a restricted passage p. The outer end of the cylinder y is formed with a port q which is controlled by a valve hereinafter described.

Assuming the swash plate e to be in a position of maximum Obliquity, that is to say, the position in which the pump gives its maximum output, the swashl plate will remain in this position so long as the valve above mentioned is closed. -But when this valve opens the liquid pressure in the outer end of the cylinder y will fall and the piston k will be moved by the fluid pressure in the other end of the cylinder against the action of the spring m, so moving the swash plate e in the direction for reducing the pump output.

The pump above described is of known construction and forms no part of the present invention.

In carrying the invention into effect as shown, I employ a hollow body r having an inlet s and an outlet t which are adapted for connection by a pipe system u to the pump outlet i and a nozzle or nozzles v respectively, the nozzle or nozzles being situated in the combustion chamber of the prime mover to be supplied with liquid fuel by the pump. Between the inlet sand outlet t there is provided in the body 1 an orifice w through which liquid fuel can flow from the inlet to the outlet, and the effective area of this orifice is variable by a slidable plug a: having a tapered o equivalent end of decreasing diameter located in the orifice. The plug is formed with an axial bore y which forms a second orifice in parallel with the first orifice w, the effective area of the second orifice being variable by the axial move-7 ment of the plug relatively to an adjustable sta` tionary plug .e of tapered or equivalent form in the body r. Flow can occur at all times through the second orifice y at a rate dependent on the relative positions of the two plugs z. But the flow through the first orifice w can be varied or interrupted by a manually operable valve 2 which is situated between the inlet s and the approach to the first orifice and which may be of the poppet type. The valve 2 is adapted to be actuated by, for example, a manually operable cam 3 (acting on the valve through a spring 4 or resilient capsule) formaintaining across the associated orifice any desired pressure drop which is independent of atmospheric pressure.

The slidable plug a; is movable in one direction by the pressure of the liquid fuel delivered by the pump (or other convenient pressure fluid) on a piston 6 connected to one end of the slidable plug, the piston being slidable in a cylinder 1 which at one end communicates with the body inlet s, and being loaded by a spring 8 which acts on the piston through la stem 9 passing through the other end of the cylinder. The second orifice y communicates with the first mentioned end of the cylinder l, and thus with the body inlet x, through radial ports Il in the end of the slidable plug a: adjacent to the piston 6. The two ends of the cylinder 'I are interconnected by the ports Ilin the slidable plug a: and a restricted passage II in the piston D, and the end of the cylinder remote from that to which the pressure fluid is admitted is provided with a vent I2, the latter beingcontrolled by a valve I3. The latter is carried by a lever I4 which is loaded by an adjustable spring I 5 and serves as an abutment for the spring I acting on the piston 6. The lever Il is connected either to a capsule which is responsive to variations of atmospheric pressure, or as shown to a pair of capsules I6, I'I one (I6) of which is evacuated and the other (I1) of which is open to the atmosphere. The arrangement is such that an increase in atmospheric pressure will open the valve I3 to cause the fluid pressure action on the piston 6 to move the plug :c in the direction for increasing the effective areas of the orifices w, y controlled by the plug. In the event of a fall of atmospheric pressure, the valve I3 closes, and the plug x is moved in the direction for restricting the orifices w, y by the spring l acting on the piston 6, this spring being stronger than the spring I5. The plug a: is stabilised when the spring B is balanced by the atmospheric pressure in the capsule I'I, and the spring I5.

The pressure difference set up between the inlet s and outlet t by variations in the effective areas of the orifices w, y is utilised to actuate the above mentioned valve of the pump controlling means, which valve is indicated by I8. This pressure difference is caused to act on opposite sides of a'fiexible spring-loaded diaphragm or capsule I8 adapted to actuate a lever 20 carrying the valve I8. The diaphragm or capsule I9 and valve I8 are preferably contained in a chamber 2| formed in the body r above mentioned. this chamber being provided with a vent 22, and the seating of the valve being connected by a pipe 23 to the POrt q in the cylinder i of the pump controlling means. But if preferred, this chamber and valve may be directly associated with the pump casing b, the opposite sides of the diaphragm orcapsule I9 being then connected by a pair of pipes to the two sides of the variable orifices w, y above described.

By the provision in the pipe system of a pair of variable orifices in parallel, the flow to one end of which is controllable manually to suit varying load requirements, and the effective areas of both of which are variable in response to changes of atmospheric pressure, I am able to regulate the rate of fuel supply in a manner suited to a wide range of variations of load and of atmospheric conditions, in a very satisfactory manner. The invention is not, however, limited to the example described, as it may be utilised in other ways for achieving the desired object. Thus it may be applied for controlling any appropriate variable delivery pump, or it may be used for controlling a valve in the delivery pipe between any convenient pump (of fixed or variable delivery) and the nozzle or nozzles, which valve may serve to throttle or to by-pass the flow.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is:

l. Means for controlling liquid fuel fiow, comprising in combination in a hollow body part having an inlet and an outlet for liquid fuel Under pressure, passageways through which liquid fuel can flow from said inlet to said outlet, and which are provided with a pair of coaxial orifices for establishing a pressure difference between said inlet and outlet, a movable member for varying the effective areas of said orifices, means responsive to atmospheric pressure for imparting movement to said member, and a manually operable valve for controlling the fiow of liquid fuel from said inlet to one of said orifices.

2. Means as and for the purpose claimed in claim 1, in which one of the orifices is formed by an axial bore in a slidable plug constituting the movable member for varying the effective areas of the orifices, the plug having an end of decreasing diameter located in the other orifice, and having associated with it a stationary plug whereby the effective area of the orifice formed by the said bore is variable in response to movement of the slidable plug.

3. Means as and for the purpose claimed in claim 1 and having in combination with the movable member for varying the effective areas of the orifices, a spring loaded piston operatively associated with the said member, a cylinder in which the piston is movable and which is adapted at opposite ends respectively for the admission and discharge of fluid under pressure, a restricted passage interconnecting the two ends of the cylinder, and a valve for controlling flow of pressure fluid from the discharge end of the cylinder, the valve being operable by the means for imparting movement to the said member.

4. Means as and for the purpose claimed in claim 1 and having in combination with the movable member for varying the effective areas of the orifices, a spring loaded piston operatively associated with the said member, a cylinder in which the piston is movable and which is adapted at opposite ends respectively for the admission and discharge of fluid under pressure, a restricted passage interconnecting the two ends of the cylinder, a valve for controlling flow of pressure uid from the discharge end of the cylinder, a spring loaded lever operable by the piston and carrying the valve, and a capsule for actuating the leverin response to variations in atmospheric pressure, the said spring loaded lever and capsule serving also as the means for imparting movement to the said member.

5. Means as and for the purpose claimed in claim 1 and having a flexible member exposed at opposite sides to the pressures at opposite sides of the two orifices, and means operable by the fiexlble member for controlling the pressure of the liquid fuel supplied to the inlet of the body part.

6. Means as and for the purpose claimed in claim 1, in which the manually operable valve comprises the combination of a seating, a closure member co-operating with the seating, a manually operable cam for actuating the closure member, and resilient means located between and interconnecting the cam and closure member.

RICHARD JOSEPH IFIELD.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,408,836 Warner Oct. 8, 1946 

